Low-head drilling [LHD] avoids differential sticking and reduces formation damage. M. Kass, J.-C. Senger and M. Sach. OGJ, 8 September 1997, 95(36), 71, 72, 74, 75.
Details are given of how differential sticking and formation damage were avoided in Germany's Uelsen gas field by LHD drilling fluids. Four storage wells were drilled and completed using this technique in the depleted Bunter sandstone reservoir. A gradient of 0.6 bar/10 m (0.265 psi/ft) was achieved using an aerated mud system. Mud systems, LHD management, drilling costs, operational experience, and completion criteria are discussed, as well as future applications.
- Journal title: Oil and Gas Journal